Forming method for optical fingerprint recognition device

Abstract

The invention provides a forming method for an optical fingerprint recognition device. The forming method comprises the steps that a silicon substrate is provided; a light transmitting substrate and an image sensor chip are provided and bonded, and a lens array is formed on the light transmitting substrate through a gradually-changing luminous flux photoetching method, wherein the lens array corresponds to a light sensing array of the image sensor chip; the silicon substrate and the light transmitting substrate are bonded, the silicon substrate is etched so that a through hole array corresponding to the lens array can be formed and the lens array can be exposed, and silicon light bars are formed between adjacent lenses. According to the forming method for the optical fingerprint recognition device, the lens array is formed through the gradually-changing luminous flux photoetching method, requirements for manufacturing of a more exquisite and complex lens can be met, optical characters needed by the optical fingerprint recognition device are accurately guaranteed, and the forming method is suitable for a portable electronic device and is compatible with an existing chip manufacturing and packaging technology so that cost can be reduced.

Description

technical field [0001] The invention relates to the field of image processing, in particular to a method for forming an optical fingerprint identification device. Background technique [0002] The current fingerprint identification schemes include optical technology, silicon technology (capacitive / radio frequency type), ultrasonic technology, etc. [0003] Optical technology The use of optical imaging equipment is based on the principle of total reflection of light (FTIR). The light hits the surface of the glass with fingerprints, and the reflected light is obtained by the image sensor. The amount of reflected light depends on the depth of the fingerprint ridges and valleys pressed on the surface of the glass, as well as the oil and moisture between the skin and the glass. After the light is shot to the center of the valley through the glass, it is totally reflected at the interface between the glass and the air, and the light is reflected to the image sensor, while the lig...

AI Technical Summary

Problems solved by technology

[0004] However, the current optical fingerprint identification devices are large in size and have a long optical path, so they cannot be applied to portable electronic devices such as mobile phones

Under the premise of limited volume, the fingerprint recognition device suitable for portable electronic devices such as mobile phones needs to use a lens with a finer and more complex three-dimensional surface to ensure the required optical properties, such as resolution. However, using traditional micro-processing technology, For example, anisotropic or isotropic dry etching and wet etching can only process surfaces with limited topography, and newly developed three-dimensional micromachining technologies such as multi-layer mask technology, laser three-dimensional lithography, and electron beam direct writing technology , there are problems such as poor accuracy, high cost, and low output, which cannot meet the production requirements of such high-precision devices.

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